The WiFi 6E standard brings with it access to the 6 GHz band, which is faster and has more channels than the 5 GHz band. So why do Orbi WiFi 6E Systems still use the 5 GHz band for their backhaul? As the frequency gets higher, WiFi speed increases but WiFi range decreases. WiFi range decreases because higher frequencies have more trouble going through walls and other objects. 2.4 GHz is the lowest WiFi frequency, which means that it has the longest range but is also the slowest. 6 GHz WiFi is incredibly fast, but can only cover a short distance. 5 GHz is the perfect balance of range and speed to make sure that your Orbi can give you both reliable coverage and great speed.
For more information about WiFi bands, see What is the difference between 2.4 GHz, 5 GHz, and 6 GHz wireless frequencies?.